1. Field of the Invention
The invention relates to the scheduled maintenance of equipment and devices. In particular, the invention relates to the maintenance of equipment in accord with a schedule based on actual usage time of the equipment. Specifically, the invention relates to apparatus which indicates the total time in use of a given piece of equipment and/or the number of times a given piece of equipment is activated and deactivated. The average time a given piece of equipment is in use each time demand is made on it is determinable.
2. Prior Art
Machinery and equipment represent money invested. The return on that investment can be drastically reduced if the machinery and equipment are not maintained, or are too seldom maintained. However, the return on investment can also be adversely affected if the machinery and equipment are subjected to too frequent, unneeded maintenance.
An engine may have a preventive maintenance schedule which requires that the valve clearances be checked every 720 hours of operation. This check will require that the engine be taken off line and that maintenance personnel expend time and effort to perform the check. This particular check will be only one of many required by the 720 hour maintenance schedule, so the overall down-time and labor expenditure may be significant. This expenditure is wasteful if done too frequently, but is trivial if performed on a reasonable basis.
Engine manufacturer's recommendations provide a good starting point for setting a maintenance schedule. However, an ideal maintenance program is one tailored to the individual engine based on records kept from the date of installation of the engine. The problem that arises in attempting to establish such records is the uncertainty which generally exists as to how many hours of operation a particular engine has been subjected to. This is especially true of large manufacturing and power generating facilities where vast amounts of equipment are irregularly cycled on and off throughout the work day.
The need exists to ascertain the actual hours of operation each machine or other piece of equipment has experienced, on an on-going basis, so that a reasonable, near ideal, maintenance program for each machine might evolve. This need has been addressed in the prior art.
All the prior art known to the inventor herein is based on the general principle of detecting the initiation of line current feeding the machine being monitored for operational time. When the line current is detected, a time measuring and accumulating device is activated. When the line current falls to zero, the timing device is deactivated, but the record of accumulated operational time of the monitored equipment is retained for reference.
The need still exists, however, for a simple, inexpensive device which can be readily installed with minimal effort or disruption of the monitored equipment circuitry. Preferably, the device for measuring the time in which operation of a machine is demanded will be readily transportable and carry its own power source. It would also be beneficial if the time demand monitoring device yields information from which the average time of operation, per operation, might be derived. It is the inventor's intent to meet these needs, and more, with the Time Demand Counter taught herein.